我有一个寻呼机片段活动：
List<Fragment> fragments = new Vector<Fragment>();
fragments.add(Fragment.instantiate(this, PastEventListFragment.class.getName(),bundle));
fragments.add(Fragment.instantiate(this, EventListFragment.class.getName(),bundle));
this.mPagerAdapter = new EventPagerAdapter(super.getSupportFragmentManager(), fragments);
//
ViewPager pager = (ViewPager)super.findViewById(R.id.viewpager1);
pager.setAdapter(this.mPagerAdapter);
pager.setCurrentItem(1);
我赶上onKeyDown事件：
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_MENU) {
}
return super.onKeyDown(keyCode, event);
}
现在的问题是：如何在我在这个活动已实例化的所有片段使用事件。 谢谢
你可以做的是在你的片段类（一个或多个）来定义一个自定义的方法。 例如：
public void myOnKeyDown(int key_code){
//do whatever you want here
}
每当一键下事件在你的Activity类中引发调用此方法。 例如：
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_MENU) {
((PastEventListFragment)fragments.get(0)).myOnKeyDown(keyCode);
((EventListFragment)fragments.get(1)).myOnKeyDown(keyCode);
//and so on...
}
return super.onKeyDown(keyCode, event);
}
如果有人interessed如何与Boradcast做到这一点：
在onViewCreated您的片段
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
// Register to receive messages.
// We are registering an observer (mMessageReceiver) to receive Intents
// with actions named "custom-event-name".
LocalBroadcastManager.getInstance(this).registerReceiver(mMessageReceiver,
new IntentFilter("activity-says-hi"));
...}
// Our handler for received Intents. This will be called whenever an Intent
// with an action named "custom-event-name" is broadcasted.
private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
// Get extra data included in the Intent
doSomethingCauseVolumeKeyPressed();
}
};
您的KeyEvent - 代码投放活动
@Override
public boolean dispatchKeyEvent(KeyEvent event) {
int action = event.getAction();
int keyCode = event.getKeyCode();
switch (keyCode) {
case KeyEvent.KEYCODE_VOLUME_UP:
if (action == KeyEvent.ACTION_DOWN) {
sendBroadcast();
}
return true;
case KeyEvent.KEYCODE_VOLUME_DOWN:
if (action == KeyEvent.ACTION_DOWN) {
sendBroadcast();
}
return true;
default:
return super.dispatchKeyEvent(event);
}
}
您的广播发件人：
private void sendVolumeBroadcast(){
Intent intent = new Intent("activity-says-hi");
LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
}
正如其他人，接受的答案导致活动及其片段之间的紧耦合提及。
我会建议使用某种形式的基于事件的执行，而不是。 这是更为可重复使用和产生更好的软件架构。 在以前的项目中，我已经使用了以下解决方案（科特林）之一：
广播
使用Android's LocalBroadcastManager： 文档
创建一个BroadcastReceiver：
class SomeBroadcastReceiver : BroadcastReceiver() {
override fun onReceive(context: Context?, intent: Intent?) {
val keyCode = intent?.getIntExtra("KEY_CODE", 0)
// Do something with the event
}
}
在您的活动：
class SomeActivity : AppCompatActivity() {
override fun onKeyDown(keyCode: Int, event: KeyEvent?): Boolean {
val intent = Intent("SOME_TAG").apply { putExtra("KEY_CODE", keyCode) }
LocalBroadcastManager.getInstance(this).sendBroadcast(intent)
return super.onKeyDown(keyCode, event)
}
}
然后，在任何片段（或服务，等等）的：
class SomeFragment : Fragment() {
val receiver = SomeBroadcastReceiver()
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
val filter = IntentFilter().apply { addAction("SOME_TAG") }
LocalBroadcastManager.getInstance(context!!).registerReceiver(receiver, filter)
return super.onCreateView(inflater, container, savedInstanceState)
}
}
EventBus
使用EventBus
创建一个事件类：
data class Event(val keyCode: Int)
在您的活动：
class SomeActivity : AppCompatActivity() {
override fun onKeyDown(keyCode: Int, event: KeyEvent?): Boolean {
EventBus.getDefault().post(Event(keyCode))
return super.onKeyDown(keyCode, event)
}
}
然后，在你的片段：
class SomeFragment : Fragment() {
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
// Register for events
EventBus.getDefault().register(this)
return super.onCreateView(inflater, container, savedInstanceState)
}
@Subscribe
public fun onKeyEvent(event : Event) {
// Called by eventBus when an event occurs
}
override fun onDestroyView() {
super.onDestroyView()
EventBus.getDefault().unregister(this)
}
}
我子类活动和片段类进行传递的KeyEvent。 对我来说，它看起来比发送本地广播清晰。 但这种解决方案可能不那么灵活。 选择自己的首选方式。
下面是活动：
public abstract class KeyEventPassingActivity extends Activity {
public interface KeyEventListener extends View.OnKeyListener {
boolean isVisible();
View getView();
}
private final List<KeyEventListener> keyEventHandlerList = new ArrayList<>();
@Override
public boolean dispatchKeyEvent(KeyEvent event) {
for (KeyEventListener handler : keyEventHandlerList) {
if (handleKeyEvent(handler, event)) {
return true;
}
}
return super.dispatchKeyEvent(event);
}
void addKeyEventHandler(@NonNull KeyEventListener handler) {
keyEventHandlerList.add(handler);
}
void removeKeyEventHandler(@NonNull KeyEventListener handler) {
keyEventHandlerList.remove(handler);
}
/**
* @return <tt>true</tt> if the event was handled, <tt>false</tt> otherwise
*/
private boolean handleKeyEvent(@Nullable KeyEventListener listener, KeyEvent event) {
return listener != null
&& listener.isVisible()
&& listener.onKey(listener.getView(), event.getKeyCode(), event);
}
}
而片段：
public abstract class KeyEventHandlingFragment extends Fragment
implements KeyEventPassingActivity.KeyEventListener {
@SuppressWarnings("deprecation")
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
if (activity instanceof KeyEventPassingActivity) {
((KeyEventPassingActivity) activity).addKeyEventHandler(this);
}
}
@Override
public void onDetach() {
Activity activity = getActivity();
if (activity instanceof KeyEventPassingActivity) {
((KeyEventPassingActivity) activity).removeKeyEventHandler(this);
}
super.onDetach();
}
}
要点： https://gist.github.com/0neel/7d1ed5d26f2148b4168b6616337159ed
